The present invention relates to a noise-damped brush holder, especially for small commutator motors, in which the holder includes a brush mount having brush boxes mounted in a brush plate with brushes disposed therein.
German Patent Document No. DE-U-81 28 614 and corresponding European Patent Document No. EP-A1-00 76 403 disclose a noise-damped brush mount for a commutator motor, in which the individual brush housings guiding the brushes are each mounted independently on a brush plate with a damping plate interposed therebetween. The brush plate accepts additional electronic and/or electrical components and is mounted directly on the motor housing. The brushes are each mounted diagonally at an angle of incidence that differs from the perpendicular to the surface of the commutator, in such fashion that in view of a leg spring pressing on one beveled end of the brush and in view of the operational frictional force between the carbon brush and the surface of the commutator on the one hand and the pressure applied by the leg spring on the other, the brush abuts one side wall of the brush housing receiving it in a fixed position over its entire radial length, regardless of the rotational direction of the commutator.
French Patent Document Nos. FR-A-22 49 468 and FR-A-26 27 821 (the latter of which corresponds to U.S. Pat. Document No. US-A-4,921,371 and German Patent Document No. DE-A-39 04 844) disclose mounting a brush holder plate on a motor end shield using damping elements.
These prior designs are complex to manufacture in that they rely on complicated arrangements of damping elements to reduce the effects of noise.